If a 9 digit number 389x6378y is divisible by 72 , then the value of 6x + 7y is:
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Correct answer: A
Explanation
The correct answer is Option 1 i.e. 64.
If a number is divisible by 72, it means it is divisible by both 8 and 9.
To make 78y divisible by 8, put y = 4
Now, the number is 389x63784
Now, sum of digits = 3 + 8 + 9 + x + 6 + 3 + 7 + 8 + 4 = 48 + x
Now, put x = 6
Required answer = 6(6) + 7(4)
⇒ 36 + 28 = 64